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The Tiny Audio Amplifier

Introduction: The Tiny Audio Amplifier

A tiny, cheap Amplifier where it can be incorporated almost anywhere. Connect your MP3,iPod,Laptop,Cell Phone... and you got your self a DIY portable stereo. It can be powered using batteries and be helpful in many cases. It is capable to drive a small 8 Ohm speaker or even a combination of a small in diameter say 2-3 inch woofer and a tweeter for better acoustics.

Attachments

Step 1: The Main Ingredient

The main ingredient is the LM386N IC witch is a low voltage audio power amplifier.
Let me stay here and say that I'm not the Columbus, who discovered America!
There are plenty of information out there, just type LM386.
To begin with...

Step 4: TOOLS You're Gonna Need

TOOLS you might need

Solder iron, not more than 25W
Solder wire for PCB soldering
Small Handheld drill
Drill bits of 0.8mm & 1mm
Plumbers Jel-flux copper cleaning paste. Helps the soldering process a lot.
Apply a small quantity of paste at the copper side of PCB, then place the components on and solder.
Small Nail cutter for cutting the components spare wire on PCB after the soldering is done.
Pure Acetone for cleaning the PCB after the soldering is done.
A few drops with the use of an old tooth brash will do the job just fine.

Step 5: OPERATION

Just to drop some ideas, there are many ways to power the amplifier.
It can be powered from a stabilized power supply, one use batteries, rechargeable batteries, AA or AAA or one 9V cell or (x2) 9V cell in parallel for longer play and many more, really it's up to you to decide.
The LM386 requires 4V – 12V to operate with typical operation at 9V.
more voltage = more acoustic power (milliwatts)
If you need a stereo amplifier (R channel + L channel) then tow (2) circuits must be constructed.

A few things you need to know...
The LM386 does all the jab with only a few external components.
Connecting C1 through [jumper SW] to IC pins 1 & 8 a GAIN of 200 is applied.
In practice you will notice an increased volume and also more distortion (not good).
The purpose of 200 GIAN can be useful in cases where the source is to low for example a microphone pre-amplifier.
In most cases if input source is an MP3 player a typical GAIN of 20 will be enough for a decent output.
Adding R1 & C5 it's optional to the circuit and acts as a BASS BOOST filter, sounds better but drops the volume a bit.

Step 6: CONSTRUCTION

Print the PCB layout as is from the given picture (72 dpi). A laser or ink jet printer can be used.
Depending on the process you will follow, turn the layout left or right.
There are many indestructible on how to print a PCB and how to etch.Follow the illustrated components picture to place the parts. Pay attention for the components polarity when stated from the parts list.
The real life picture showing the amp is from an earlier version and works great.
The illustrated one it is a bit larger but have enough room for the connectors.

I am open to any questions, comments and suggestions and hope this instructable was helpfulHave fun!

I'm afraid i have lost some files with the actual pcb dimensions. The below dimensions given are for the Ver.:1, the first 3 pictures of the instructable. For those who wish to use the Ver.:2, the illustrated ones here is a tip. Use a paint App like corel photo-paint. At the print process shrink the illustrated pcb image to the point the LM386 ic pins fit to the printed holes of the printed pcb. This is a try and error process and i know it's not the best way, i am sorry for that.

I'm sorry for the delay guys but it's summer time, you know... Anyway, PCB width = 28.5mm x PCB height = 25.5mm form border to border. If it is to use the Amp as audio/music instrument it's best to add the low filter (R1 + C2) to the circuit as it acts like a bass boost. Now, if for any reason you do not wish to use the low filter use a wire between PIN1 and PIN5 of LM386. C1 capacitor (MAX GAIN) boosts the volume and again if you are intent to use the Amp as music instrument it's best to add the C1. If for any reason you do not wish to add C1 simply removed. SW (switch) added to connect/disconnect the C1 and can be removed from the PCB. Remember to connect a wire between C3's positive pin and LM386's pin 5.